Several publications are known that describe the exchange of the ring back tone with a configurable ring back tone. These publications are described below, and each is incorporated herein by reference.
For example, International Application Publication No. WO 00/49793 to Kim Kangsuk et al., discloses an advertising method by using a ring-back tone. According to WO 00/49793, a controller employed in a sender-side switching system recognizes a sender's telephone number and a receiver's telephone number dialed at the sender's telephone set. Then the receiver's telephone number is transmitted to a receiver-side switching system at a calling stage. The receiver-side switching system checks the state of the receiver's telephone, e.g., ready or busy, and, subsequently, sends, e.g., a ring-back tone in conformity to the state to the sender-side switching system. The sender-side switching system receives the ring-back tone. In case the ring-back tone is a busy tone, the sender-side switching system forwards the busy tone to the sender's telephone set. Otherwise, that is, the ring-back tone is a ringing tone which implies that the receiver's telephone is ready to receive a call, the sender-side switching system searches registered member information by consulting a database linked to the controller and checks if the receiver's telephone number matches a registered member in the database. If the sender is determined not to be a registered member, the sender-side switching system forwards the ring-back tone; otherwise it sends a predetermined advertisement message stored in an advertisement memory to the sender's telephone set. If a response, e.g., a hook-off, from the receiver's telephone is perceived or if the sender terminates the call, the sender-side switching system stops the sending of the advertisement message.
International Application Publication No. WO 00/62524 to Han Dong Shik discloses a ring back tone/busy tone selection-type communication in which instead of conventional tones, a music signal and an information voice signal is transmitted to the caller.
Japanese Application Publication No. JP 11-275,232 to Yabusaki Masami et al. identifies the need to provide a system capable of sending a high-efficiency voice coded ring back tone to a line by transmitting music or voice set by a customer to the terminal of a communicating party as a customer-original ring back tone. JP 11-275,232 discloses a call controller that instructs a voice storage calling device to transmit a ring back tone through a communication line to another exchange. The voice storage calling device selects a ring back tone corresponding to a callee and sends the selected ring back tone to a call originating terminal. The customer can transmit any music or voice to the terminal of a party as a customer-original ring back tone.
US Patent Application Publication No. US2004174983A to Arbel Benny et al. discloses a method and a system for providing configurable call progress tones in a telephony session by identifying a receiver of the telephony session, selecting a tone in accordance with the preferences of the receiver and providing a configurable call progress tone of the selected tone.